The present invention relates to hand held sprayers for spraying various aerosol products, more particularly to dual receptacle sprayers having a first receptacle for containing the product to be dispensed and a second receptacle for containing a pressurized propellant to dispense the product.
Dual receptacle sprayers of various types are well known, including sprayers having side by side receptacles, sprayers having piggyback receptacles wherein a propellant receptacle is positioned on top of a product receptacle, and sprayers wherein a propellant receptacle is positioned within a product receptacle to form inner and outer receptacles. A particular advantage of such dual receptacle sprayers is that they lend themselves to the use of less propellant and higher product to propellant ratios at the discharge outlet, very desirable features in view of the expense and environmental concerns relating to commonly used aerosol propellants such as those containing volatile organic compounds. In dual receptacle sprayers of the piggyback or inner-outer type, an aerosol valve is mounted at the top of the propellant receptacle and contains a valve stem through which both product and propellant can pass into an actuator mounted on the top of the valve stem. A conduit for the product is positioned below the valve and passes in sealed fashion through the inside and out of the bottom of the propellant receptacle down into the product receptacle. A Venturi constriction is present in the actuator, and when the aerosol valve is actuated, the flow of propellant from the propellant receptacle through the valve and through the Venturi constriction draws product from the product receptacle through the conduit and valve into the actuator to mix with the propellant and be dispensed from the actuator.
For a satisfactory dual receptacle sprayer having inner propellant and outer product receptacles, there are a large number of criteria that need to be addressed and satisfied. First of all, the sprayer needs to be safe from rupture of the propellant receptacle causing injury to the user. Second, the sprayer needs to be safe from propellant inadvertently entering the product receptacle upon actuator clogging or due to poorly designed propellant receptacle placement, to cause rupture of the product receptacle and injury to the user. Third, propellant should not in any event inadvertently enter the product receptacle upon actuator clogging or because of poorly designed propellant chamber and valve placement, since the inadvertent adding of propellant to the product will change the predetermined product to propellant ratio to be dispensed when the sprayer is later actuated (for example, after the clogged actuator is cleaned). Fourth, the sprayer packaging should be economical to manufacture and aesthetically pleasing in appearance to the user, both in shape, feel and graphics of the overall package. Fifth, the product in the product receptacle should not be open to the atmosphere so that when the sprayer is not in use, the product in the product receptacle cannot evaporate, be contaminated, or be released from the sprayer by dropping the sprayer or squeezing the outer product receptacle. Sixth, the design of Venturi constriction in the actuator should provide high product to propellant ratios for the aforementioned reasons. Seventh, the product receptacle advantageously may be refillable, and the propellant receptacle and valve can be replaceable for interchangeability and reuse in dispensing various products. The closure of the propellant receptacle and its seating within the product receptacle should be simple to manufacture and designed to prevent any blow-off of the closure by the propellant. Eighth, the propellant receptacle and valve structure advantageously may be designed to permit high speed pressure filling of the propellant receptacle through valve structure which must also be adapted for product flow during spraying, while excluding propellant flow from entering the product flow path of the valve structure during said pressure filling. Pressure filing of volatile organic propellant components is advantageous vis-a-vis under the mounting cup filling for environmental and economic reasons, as is well known, and smaller amounts of expensive propellant can be used. Ninth, the valving structure for both product and propellant flow through the housing and stem of the valve should be simple in construction and manufacture. Tenth, means should be provided to maintain atmospheric pressure in the product receptacle as product is sprayed, so that as the product is drawn out of the product receptacle the product receptacle will not distort or collapse inwardly because of lowered internal pressure. At least these criteria are relevant to a commercially satisfactory, economical and safe sprayer having inner and outer receptacles.
The prior art to date has at best only partially satisfied the above criteria for sprayers with inner and outer receptacles. In certain of the prior art, the propellant receptacle is the outer receptacle so that rupture immediately exposes the user to injury. Other prior art places the propellant chamber inside the propellant chamber, but provides no means to prevent propellant, upon clogging of the actuator nozzle or unsatisfactory valve-propellant receptacle placement, from finding a path into the product chamber to potentially cause rupture or as a minimum change the ultimate product to propellant ratios dispensed. Certain other such prior art variously provides complicated and/or inadequate means to suspend the propellant receptacle within the product receptacle, which means can be blown off the top of the propellant receptacle and which allow seepage from the propellant receptacle into the product receptacle through a valve sealing gasket; complicated designs for the propellant and product valves; no valve shut-off of the product container when the sprayer is not being used; inadequate Venturi constructions; and/or no means to pressure fill the propellant receptacle.
Representative of the above prior art are U.S. Pat. Nos. 3,289,949; 3,388,838; 3,389,837; 3,401,844; 3,451,596; 3,894,659; 4,441,632; 5,507,420; and 6,092,697.
The present invention provides a dual receptacle aerosol spray dispenser having a thin, flexible plastic outer receptacle adapted to contain the product to be dispensed. An inner, substantially rigid, receptacle is seated within the outer receptacle and is adapted to contain a pressurized propellant out of contact with the product to be dispensed. A closure in the form of an aerosol valve mounting cup or the like sealingly closes the top of the inner receptacle. Centrally positioned on the closure is an aerosol valve assembly having an aerosol valve housing, a valve stem extending out of the closure, and a primary valve for controlling flow from the propellant receptacle. A product conduit from the lower end of the valve housing extends through the inner propellant receptacle into the outer product receptacle. The aerosol valve assembly also includes a secondary shut-off valve for controlling flow from the product receptacle, whereby product flow cannot occur through the secondary valve and out of the sprayer when the sprayer is not in use, and contamination or evaporation of the product in the product receptacle accordingly will not occur. The valve stem includes upwardly extending bores open at their upper ends, one of said bores being in fluid communication with the primary valve and another of said bores being a central bore in fluid communication with the secondary valve. A spray actuator is mounted on the top of the valve stem, overlies the upper ends of said bores, has a discharge opening, and contains a particularly efficient insert with a Venturi constriction to obtain high product to propellant ratios. The valve stem further includes transverse orifices communicating with the propellant and product bores, and first upper and second lower flexible sealing gaskets transversely aligned with and blocking the transverse orifices when the sprayer is not in use.
Upon use of the sprayer, the actuator discharge opening can occasionally clog, which can lead to a dangerous safety issue if propellant entering the actuator should, because it cannot exit the clogged discharge opening, pass down the product bore of the stem past the secondary shut-off valve, down the product conduit and into the outer thin plastic product receptacle. A sufficient pressure build-up by this means can cause the outer container to rupture and potentially injure the user. Even without such a rupture, sufficient propellant can enter the product receptacle by this means such that, after the clogged actuator discharge outlet is cleaned, the resulting product and propellant dispensed on subsequent spraying will have a considerably different product to propellant ratio then the predetermined desired ratio. This latter result, in addition to the use of excess propellant, also will effect particle size and spraying pattern of the sprayed product and thus the effectiveness of the spraying. Accordingly, a tertiary one-way valve is provided downstream of the secondary shut-off valve in the valve housing or in the conduit in the path of product flow, the said tertiary valve being adapted to close upon the aforementioned clogging to prevent any misdirected propellant entering the flexible outer product receptacle.
The inner receptacle may have the mounting cup clinched about a peripheral bead of the receptacle, which is in turn seated on a ledge of the outer receptacle adjacent its upper end and which may be retained thereon by a screw or snap cap. Pressure equalization means is also provided for the outer container as product is dispensed.
In addition, pressure filling of propellant is provided for in the present invention by pressure filling paths emanating from around the valve stem where said stem passes through the mounting cup, a first path during pressure filling extending over the top of the first upper flexible gasket and around its outer deflected edge through a plurality of passages into the inner receptacle, and a second path during pressure filling extending over the top of the first upper flexible gasket, around its inner deflected edge into the interior of the valve housing, and through side wall openings of the valve housing into the inner receptacle. The side wall openings of the valve housing are placed between the primary and secondary valves, and propellant during filling cannot pass from inside the valve housing to any part of the product flow path become of the presence of the second lower flexible gasket.
Other features and advantages of the present invention will be apparent from the following description, drawings and claims.